Vehicle control device

Abstract

To provide a control device of a vehicle that can properly control acceleration and deceleration of the vehicle, even if unforeseen shaking occurs in the vehicle due to earthquake or the like during ACC control.SOLUTION: In a control device of a vehicle, which can perform ACC control, a controller determines a direction of shock of earthquake, when detecting occurrence of earthquake during execution of following-travelling control included in ACC control (a step S2: YES); performs the following-travelling control so that the vehicle is suppressed from approaching a preceding vehicle (a step S8) when determining that the direction of the shock of the earthquake is same as a longitudinal direction of the vehicle (a step S7: YES); and performs constant-speed travelling control so that the vehicle is suppressed from being accelerated (a step S11) when determining that the preceding vehicle does not exist (a step S10: YES) when determining that the direction of the shock of the earthquake is same as a lateral direction of the vehicle (a step S9: YES).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that performs adaptive cruise control (ACC). [Background technology]

[0002] Patent Document 1 discloses a vehicle cruise control device that is configured to change the rate at which deceleration is reduced until braking is released depending on the deceleration when the preceding vehicle disappears (the preceding vehicle is lost) during braking. In the device of Patent Document 1, if the deceleration when the preceding vehicle is lost is large, the rate at which deceleration is reduced is reduced to suppress shock, and if the deceleration when the preceding vehicle is lost is small, the rate at which deceleration is reduced is increased to quickly release braking.

[0003] Patent Document 2 discloses a driving control device that slows down or stops a vehicle when an earthquake occurs or an emergency earthquake alert is received during autonomous driving. In the device of Patent Document 2, if the vertical or lateral shaking of the vehicle is greater than a predetermined value, the allowable distance between the vehicle and the following vehicle is set to be short, and the vehicle is strongly decelerated so that it can immediately decelerate and stop. It is noted that the longitudinal shaking of the vehicle can be allowed to be somewhat large because it has little effect on tire grip. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-216776 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-146168 Summary of the Invention [Problem to be solved by the invention]

[0005] In the device of Patent Document 1, if an unexpected lateral shaking of the vehicle occurs due to an earthquake or the like, there is a possibility that the preceding vehicle will be repeatedly lost and detected, and the acceleration and deceleration of the vehicle may not be controlled correctly. In the device of Patent Document 2, if a relatively large longitudinal shaking of the vehicle occurs when the allowable distance between the vehicle and the following vehicle is set short, there is a risk that the distance between the vehicle and the following vehicle will become excessively short. Therefore, there is room for improvement in the driving control when an earthquake occurs while the driving of the host vehicle is being controlled in accordance with the vehicles in front and behind.

[0006] The present invention has been made in light of the above technical problems, and aims to provide a vehicle control device that can appropriately control the acceleration and deceleration of a vehicle even when unexpected shaking occurs in the vehicle due to an earthquake or the like while adaptive cruise control is being performed. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a vehicle control device capable of adaptive cruise control, which controls a driving force source and a brake device to maintain a predetermined inter-vehicle distance, thereby performing follow-up control to make the vehicle follow a preceding vehicle, and constant speed control to make the vehicle travel at a predetermined speed when the preceding vehicle is not present, and the vehicle control device is provided with a controller for controlling the driving force source and the brake device, the controller including a preceding vehicle determination unit that determines whether the preceding vehicle is present in front of the vehicle, an earthquake determination unit that detects the occurrence of an earthquake, and a control unit that detects the shaking of the earthquake when the earthquake occurs. and detecting the longitudinal and lateral components of the vehicle, and determining the main vibration of the vehicle in the longitudinal and lateral directions based on the longitudinal and lateral components. and a vibration direction determination unit that determines a direction of the earthquake, and when the occurrence of the earthquake is detected by the earthquake determination unit while the following travel control is being executed, the vibration direction determination unit determines the direction of the earthquake. The main fluctuations of The direction of the earthquake is determined. The main direction of the shaking is In the case of the longitudinal direction of the vehicle, the following travel control is performed so as to prevent the vehicle from approaching the preceding vehicle, The main fluctuations ofWhen the direction of the preceding vehicle is the left-right direction of the vehicle, if the preceding vehicle determination unit determines that the preceding vehicle does not exist, the constant speed traveling control is performed to suppress acceleration of the vehicle. [Effects of the Invention]

[0008] According to the vehicle control device of the present invention, when an earthquake occurs during follow-up cruise control under ACC control, The main direction of shaking is the front-to-rear direction of the vehicle and the left-to-right direction of the vehicle (hereinafter simply referred to as the shaking direction). The system controls the acceleration and deceleration of the vehicle accordingly. In the case of longitudinal sway, maintaining a long inter-vehicle distance can prevent the vehicle from getting too close to the vehicle ahead. In the case of lateral sway, maintaining the vehicle speed even if the vehicle ahead is lost can prevent hunting in the acceleration and deceleration of the vehicle, even if the vehicle ahead is repeatedly detected and lost due to sway. Therefore, even in the event of an earthquake, the ACC control can be used to keep the vehicle running safely. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a vehicle equipped with a control device according to an embodiment of the present invention. [Figure 2] 3 is a flowchart illustrating an example of control executed by a control device according to an embodiment of the present invention. [Figure 3] 10 is a map showing the relationship between the rate of change of the distance from the preceding vehicle and the acceleration / deceleration gain of the vehicle speed during ACC control. [Figure 4] 10 is a flowchart illustrating a part of another example of control executed by the control device according to the embodiment of the present invention. [Figure 5] FIG. 5 is a diagram illustrating another part of the flowchart shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] A vehicle according to an embodiment of the present invention is capable of adaptive cruise control (ACC), which performs either follow-up cruise control, in which the vehicle follows a preceding vehicle while maintaining a predetermined distance therebetween and automatically accelerates or decelerates in response to changes in the vehicle's speed, or constant-speed cruise control, in which the vehicle travels based on a speed set by a driver or other user. Fig. 1 schematically illustrates a vehicle Ve configured in this manner. As shown in Fig. 1, the vehicle Ve includes a driving force source 1, a brake device 2, wheels 3, an ECU (electronic control unit) 4, and a detection unit 5. The driving force source 1 is a conventionally known engine, motor-generator, or the like, and outputs torque for generating driving force for the vehicle Ve.

[0011] The brake device 2 is a device similar to a conventionally known brake device, and is, for example, a friction brake such as a disc brake, drum brake, or powder brake, and is configured to generate frictional force by hydraulic pressure or electromagnetic force, thereby generating a braking force in a direction that stops the rotation of each wheel 3. The brake device 2 outputs braking torque not only in response to the driver's brake operation, but also through the operation of a VSC actuator (not shown). The VSC actuator, for example, individually increases, decreases, or maintains the wheel cylinder pressure of the vehicle Ve, thereby individually adjusting the braking force generated at each wheel 3. The VSC actuator is, for example, provided on a hydraulic path of brake oil, and performs vehicle stability control (VSC) of the vehicle Ve by controlling the braking torque applied to each wheel 3.

[0012] The ECU 4 corresponds to the "controller" in the embodiment of the present invention and is mainly composed of, for example, a microcomputer, and is configured to perform calculations using data input from the detection unit 5 and pre-stored data, and to output a control command signal based on the calculation results. The input data includes, for example, the wheel speed, steering angle, yaw rate, and oil pressure to the brake device 2. The ECU 4 also includes a VSC-ECU 4a, a preceding vehicle determination unit 4b, an earthquake determination unit 4c, and a seismic direction determination unit 4d.

[0013] The VSC-ECU 4a acquires the acceleration, yaw rate, and steering angle of the vehicle Ve, and performs control to stabilize the behavior of the vehicle Ve. Based on the acquired data related to the behavior of the vehicle Ve, the VSC-ECU 4a operates the above-mentioned VSC actuator to control the wheels 3 to be controlled so as to output braking torque according to the situation.

[0014] The preceding vehicle determination unit 4b determines a vehicle Ve that is present ahead on the same lane as the lane the vehicle Ve is currently traveling in. The preceding vehicle determination unit 4b acquires detection results from, for example, a preview camera, a radar sensor such as a millimeter-wave radar, an ultrasonic sensor, a LiDAR, etc., and calculates the presence of a preceding vehicle and the distance between the vehicle Ve and the preceding vehicle based on this information.

[0015] The earthquake determination unit 4c determines the occurrence of an earthquake based on data acquired by the detection unit 5, external notifications, etc. This determination of the occurrence of an earthquake may be performed by a conventionally known control, such as when an earthquake early warning is acquired by an earthquake early warning receiver (not shown), or by a control disclosed in Japanese Patent Application Laid-Open No. 2014-153750 that determines the occurrence of an earthquake based on a change in acceleration of the vehicle Ve and its duration, or by a control disclosed in Japanese Patent Application Laid-Open No. 2008-224353 that determines the occurrence of an earthquake based on the difference between the amount of movement and attitude of the vehicle Ve based on an image captured by an on-board camera and the amount of movement and attitude of the vehicle Ve based on a sensor of the vehicle Ve.

[0016] The vibration direction determination unit 4d detects the vibration components of an earthquake when the earthquake determination unit 4c detects the occurrence of an earthquake. The vibration direction determination unit 4d acquires data on changes in acceleration in the front-rear, left-right, and up-down directions of the vehicle Ve, and determines the direction of the main vibration of the earthquake based on the average value of the amount of change per unit time, etc.

[0017] The detection unit 5 is a device or apparatus for acquiring various data and information required to control the vehicle Ve. The detection unit 5 includes a wheel speed sensor 5a for detecting the wheel speed of each wheel 3, a vehicle speed sensor 5b for detecting the vehicle speed from the rotational speed of the wheels 3, a yaw rate sensor 5c for detecting the rate of change in the yaw angle of the vehicle Ve, an acceleration sensor 5d for detecting the acceleration in the front-rear and left-right directions of the vehicle Ve, and a master cylinder pressure sensor 5e for detecting the hydraulic pressure acting on the master cylinder of the brake device 2. The detection unit 5, ECU 4, and each actuator configured as described above are electrically connected to each other by, for example, a CAN or a wire harness, and output electric signals corresponding to detected values ​​or calculated values ​​to the ECU 4 as detection data.

[0018] Fig. 2(a) shows a flowchart that is an example of control executed by the ECU 4. First, in this flowchart, as shown in Fig. 2, control is performed in step S1 to determine whether an earthquake has occurred. As described above, the occurrence of an earthquake is determined by receiving an earthquake early warning, by changes in the lateral (front-back, left-right) and longitudinal acceleration of the vehicle Ve, or by image processing of an on-board camera.

[0019] After control for determining the occurrence of an earthquake is executed in step S1, the process proceeds to step S2, where it is determined whether an earthquake has actually occurred. The term "an earthquake has actually occurred" here refers to, for example, when the seismic intensity or magnitude is greater than a predetermined value, or when so-called main waves (S waves) of an earthquake are occurring. For example, as described above, this may be the case when waveforms indicating changes in acceleration in the longitudinal, lateral, and vertical directions of the vehicle Ve are determined to be changes specific to an earthquake, or when the movement and attitude of the vehicle Ve based on image processing of the onboard camera and the data detected by the detection unit 5 are determined to be changes specific to an earthquake. For example, it may be determined that an earthquake has occurred when one of three determinations, including the receipt of an earthquake early warning, or two or more of the three determinations, is true. If a negative determination is made in step S2 because an earthquake has not occurred, this flowchart is temporarily terminated without executing the subsequent control.

[0020] If a positive determination is made in step S2 because an earthquake has occurred, the process proceeds to step S3. In step S3, it is determined whether or not the vehicle Ve is executing ACC control. Whether ACC control is being executed is determined, for example, by whether a switch for selecting execution of ACC control provided on the instrument panel of the vehicle Ve is turned on, or whether the vehicle Ve is in an automatic driving state. If a negative determination is made in step S3 because ACC control is not being executed, the process ends without executing any further control. Note that the execution of ACC control here refers to a state in which the vehicle Ve is following a preceding vehicle.

[0021] If the answer to the question in step S3 is affirmative because ACC control is being executed, the process proceeds to step S4. In step S4, MAP1 is selected from the following distance control gain map used to control the acceleration / deceleration of the vehicle Ve according to the distance between the vehicle Ve and the preceding vehicle during ACC control. As shown in FIG. 3, this following distance control gain map is a map for accelerating or decelerating the vehicle Ve according to the rate of change of the distance between the vehicle Ve and the preceding vehicle. MAP1 shown in FIG. 3 is a reference map set when ACC control is executed, and is set so that the distance between the vehicle Ve and the preceding vehicle falls within a predetermined range. Therefore, for example, if the rate of change of the distance between the vehicle Ve and the preceding vehicle increases in the positive direction, the distance between the vehicle Ve and the preceding vehicle becomes shorter, and the vehicle Ve is controlled to decelerate using a gain according to that rate of change. Once MAP1 is selected for the following distance control gain map, the process proceeds to step S5.

[0022] In step S5, it is determined whether a predetermined time has elapsed since the occurrence of the earthquake. This predetermined time is set, for example, to a time sufficient to distinguish the components of the earthquake shaking based on the change in acceleration over time when the earthquake shaking is observed by the acceleration sensor 5d. If the determination in step S5 is negative because the predetermined time has not elapsed since the occurrence of the earthquake, the flow chart is temporarily terminated without executing the subsequent control.

[0023] On the other hand, if the predetermined time has passed since the occurrence of the earthquake and the answer is affirmative in step S5, the process proceeds to step S6. In step S6, first, data on the absolute values ​​of the amount of change in acceleration per unit time over the predetermined time period is acquired for each of the longitudinal and lateral directions of the vehicle Ve, and their average values ​​are calculated. From the calculated average longitudinal value GXave and average lateral value GMave, a determination value A for determining the direction of the earthquake shaking is calculated based on the following equation (1), and the process proceeds to step S7. A = GXave / MAX(GYave,1) …(1)

[0024] In step S7, it is determined whether the determination value A is greater than a first threshold value Th1. This first threshold value Th1 is a value that is used to determine the direction of shaking caused by an earthquake. Promote the direction This is a value for determining whether the vehicle Ve is moving forward or backward, and is set to any value equal to or greater than 1. If the determination value A is greater than the first threshold value Th1, and therefore it is determined that the vehicle Ve is moving forward or backward more than the vehicle Ve is moving left or right, the process proceeds to step S8.

[0025] In step S8, MAP2 is selected from the maps shown in FIG. 3. As shown in FIG. 3, MAP2 is set so that deceleration of the vehicle Ve starts at a smaller rate of change in the inter-vehicle distance when the vehicle Ve approaches the preceding vehicle, compared to MAP1. In other words, the threshold value on the short inter-vehicle distance side of the predetermined range is increased to prevent the inter-vehicle distance from becoming too short. Also, since deceleration starts relatively early, the rate of increase in deceleration after deceleration starts is slower than in MAP1. Note that when the inter-vehicle distance from the preceding vehicle becomes long, the same map as MAP1 is used because the possibility of a collision is low. Once MAP2 is set in the inter-vehicle distance control gain map, this flowchart ends.

[0026] If the determination in step S7 above is negative because the determination value A is equal to or less than the first threshold value Th1, the process proceeds to step S9. In step S9, it is determined whether the determination value A is smaller than the second threshold value Th2. The second threshold value Th2 is a value for estimating the direction of shaking caused by an earthquake and is set to any value equal to or less than "1." If the determination value A is smaller than the second threshold value Th2 and therefore it is determined that the shaking in the left-right direction of the vehicle Ve is greater than the shaking in the forward-backward direction, the process proceeds to step S10.

[0027] In step S10, it is determined whether the preceding vehicle has been lost. Whether the preceding vehicle has been lost is determined based on whether an on-board camera, sensor, etc. has detected the preceding vehicle within a predetermined range ahead of the vehicle Ve. If the preceding vehicle determination unit 4b determines that a preceding vehicle is present, this flowchart is temporarily ended without executing any further control.

[0028] On the other hand, if the answer to step S10 is YES because the preceding vehicle has been lost, the process proceeds to step S11. In ACC control, if the preceding vehicle is lost while the vehicle is following the preceding vehicle, the vehicle Ve is accelerated to a preset speed and driven at a constant speed. In step S11, the vehicle speed set at that time is set to the vehicle speed at the time the preceding vehicle was lost, and the vehicle speed is maintained. Thereafter, this flowchart is temporarily ended. Note that in step S11, acceleration may be suppressed, or the start of acceleration may be delayed by delaying the time until it is determined that the preceding vehicle has been lost.

[0029] If a negative determination is made in step S9 above because the determination value A is equal to or greater than the second threshold value Th2, the process proceeds to step S12, where ACC control is temporarily terminated. If an earthquake is detected, the negative determinations in steps S7 and S9 above are unlikely, and the detection unit 5 may not have correctly recognized the acceleration of the vehicle Ve. In other words, there is a risk that the ACC control will not be able to accurately estimate the positional relationship with the preceding vehicle, so the driver and passengers are notified and ACC control is terminated.

[0030] In the embodiment of the present invention configured as described above, if an earthquake occurs during ACC control, ACC control is performed according to the direction of the earthquake shaking. In other words, if the vehicle Ve is experiencing significant longitudinal shaking and the inter-vehicle distance to the preceding vehicle is short, deceleration of the vehicle Ve begins earlier than in normal ACC control. This prevents the vehicle Ve from unintentionally approaching the preceding vehicle excessively due to an earthquake. Furthermore, if the vehicle Ve is experiencing significant lateral shaking and the preceding vehicle is lost, the vehicle speed at the time the preceding vehicle was lost is maintained and the vehicle transitions to steady driving. This prevents hunting in acceleration and deceleration even when the preceding vehicle is repeatedly detected and lost. Furthermore, if the positional relationship with the preceding vehicle cannot be estimated, ACC control is temporarily terminated, preventing the vehicle Ve from behaving unintentionally.

[0031] Next, another example of control executed by the ECU 4 in the embodiment of the present invention will be described with reference to Figures 4 and 5. In the flowcharts of the other examples described below, steps that are the same as steps that have already been described will be assigned the same reference numerals, and their description will be omitted or simplified.

[0032] As shown in Fig. 4, in the flowchart of this alternative example, the same control as steps S1 to S4 in the flowchart shown in Fig. 2 is carried out. Next, the process proceeds to step S13, where it is determined that a first predetermined time or more has elapsed since the occurrence of the earthquake. This first predetermined time is set to a time sufficient to distinguish the components of earthquake shaking, similar to the predetermined time described above, but is set to a time shorter than the predetermined time described above. If the first predetermined time has not elapsed and the result of the determination in step S13 is negative, the process of this flowchart is temporarily terminated.

[0033] On the other hand, if the first predetermined time has elapsed and the answer in step S13 is affirmative, the process proceeds to step S14, where it is determined that a second predetermined time has elapsed since the first predetermined time has elapsed. This second predetermined time is set based on the same criteria as the first predetermined time, and may be approximately the same length of time as the first predetermined time.

[0034] If the second predetermined time has not yet elapsed since the first predetermined time has elapsed and therefore the result of step S14 is negative, the process proceeds to step S15. In step S15, data relating to the absolute values ​​of the amount of change in acceleration per unit time during the first predetermined time is acquired for each of the longitudinal and lateral directions of the vehicle Ve, and their average values ​​are calculated. From the calculated average value GXave1 in the longitudinal direction and the average value GYave1 in the lateral direction, a first determination value A1 for determining the direction of shaking caused by an earthquake is calculated based on the following equation (2). In other words, the same calculation as in step S6 described above is performed based on the first predetermined time. A1=GXave1 / MAX(GYave1,1) …(2)

[0035] Once the first determination value A1 is calculated, the process proceeds to step S16, where it is determined whether the first determination value A1 is greater than the first threshold value Th1. If the first determination value A1 is greater than the first threshold value Th1 and the determination in step S16 is affirmative, the control in step S8 described above is performed, and this flowchart is temporarily terminated.

[0036] Conversely, if the first determination value A1 is equal to or less than the first threshold value Th1 and the determination in step S16 is negative, the process proceeds to step S17, where it is determined whether the first determination value A1 is less than the second threshold value Th2. If the determination in step S17 is positive because the first determination value A1 is less than the second threshold value Th2, the controls of steps S10 and S11 described above are executed, and this flowchart is temporarily terminated. Conversely, if the determination in step S17 is negative because the first determination value A1 is equal to or greater than the second threshold value Th2, this flowchart is temporarily terminated. At this time, unlike the flowchart in FIG. 2, the ACC control is not terminated. This is because the first predetermined time is short and the direction of the earthquake shaking will be determined again after the second predetermined time has elapsed.

[0037] If the second predetermined time has elapsed since the first predetermined time in step S14, and the result of the determination in step S14 is affirmative, the process proceeds to step S18, where the same calculation as in step S15 is performed based on the second predetermined time. That is, a second determination value A2 for the second predetermined time is calculated based on the average value GXave2 of the absolute values ​​of the amount of change in acceleration per unit time in the forward / backward direction and the average value GYave2 of the absolute values ​​of the amount of change in acceleration per unit time in the left / right direction, according to the following formula (3), and the direction of shaking is determined. A2=GXave2 / MAX(GYave2,1) …(3)

[0038] 5, once the second determination value A2 is calculated, the process proceeds to step S19, where it is determined whether the second determination value A2 is greater than the first threshold value Th1. If the second determination value A2 is greater than the first threshold value Th1 and the determination in step S19 is affirmative, the control in step S8 described above is performed, and this flowchart is temporarily terminated.

[0039] Conversely, if the second determination value A2 is equal to or less than the first threshold value Th1 and the determination in step S19 is negative, the process proceeds to step S20, where it is determined whether the second determination value A2 is smaller than the second threshold value Th2. If the determination in step S20 is positive because the second determination value A2 is smaller than the second threshold value Th2, the controls in steps S10 and S11 described above are executed, and this flowchart is temporarily terminated. Conversely, if the determination in step S20 is negative because the second determination value A2 is equal to or greater than the second threshold value Th2, the control in step S12 described above is executed, and this flowchart is temporarily terminated.

[0040] In another embodiment of the present invention configured as described above, the predetermined time is shortened and divided into two periods, and the direction of earthquake shaking is controlled to be identified in each period. Therefore, even if the direction of earthquake shaking differs immediately after the occurrence of an earthquake and after a certain period of time has passed, the direction of earthquake shaking can be accurately detected. Therefore, earthquake shaking can be accurately detected, and ACC control can be performed according to the shaking. [Explanation of symbols]

[0041] Vehicle 1. Driving force source 2 Brake device 4 ECU (controller) 4b Leading vehicle determination section 4c Earthquake determination section 4d Vibration direction determination section

Claims

[Claim 1] A vehicle control device capable of adaptive cruise control that controls a driving force source and a brake device to maintain a vehicle-to-vehicle distance within a predetermined range, thereby performing follow-up running control to make the vehicle run so as to follow a preceding vehicle, and performing constant speed running control to run the vehicle at a predetermined speed when the preceding vehicle is not present, a controller for controlling the driving force source and the brake device; The controller a preceding vehicle determination unit that determines whether the preceding vehicle is present ahead of the vehicle; an earthquake determination unit that detects the occurrence of an earthquake; a vibration direction determination unit that, when the earthquake occurs, detects longitudinal and lateral components of the earthquake shaking of the vehicle and determines the main shaking direction of the vehicle between the longitudinal and lateral directions based on the longitudinal and lateral components, when the earthquake determination unit detects the occurrence of an earthquake while the following cruise control is being performed, the vibration direction determination unit determines the direction of the main vibration of the earthquake; When the main shaking direction of the earthquake is in the longitudinal direction of the vehicle, the following cruise control is performed to prevent the vehicle from approaching the preceding vehicle. When the main shaking direction of the earthquake is in the left-right direction of the vehicle, if the preceding vehicle determination unit determines that the preceding vehicle does not exist, the constant speed traveling control is performed to suppress acceleration of the vehicle. A vehicle control device characterized by being configured as follows.

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